Immediate electrocochleographic changes have been studied in a series of patients following intravenous infusion of either tobramycin or gentamicin. In patients receiving tobramycin, as soon as peak serum levels of antibiotic were reached, a dramatic decrease occurred in the magnitude of the compound VIII nerve action potential (AP), and of the cochlear microphonic (CM). The shape of the AP also changed. The N1 component of the waveform became very small, and N2 increased in size; this is the dissociated pattern of basal coil cochlear damage. The speed of onset of these electrical changes and their apparent reversibility suggests a temporary metabolic block caused by tobramycin. No such changes were observed following infusion of gentamicin.

Acquired stenosis of the external auditory canal is known to be a surgical problem. This is indicated by the fact that numerous techniques have been devised. A simple but successful technique has been used by the authors. Excision of the subepithelial stenotic tissue and a wedge of skin from the floor of the external auditory canal is done, and a rubber tube is inserted inside the external canal for six weeks. Thirteen out of 16 operations have shown the validity of this technique.

Stenosis of the external auditory canal (Fig. 1) has various aetiological causes, and the stenotic area may affect the whole length of the external auditory canal or just a small segment.

In view of the fact that so many possible causes exist, numerous techniques have been used to treat this problem surgically, and this illustrates that the repair may be difficult.

Considerable pessimism appears in the literature. Reference to failures may be found in many publications (Anthony, 1957; Beales, 1974). A simple but effective technique is needed, and this is our aim.